1. Berthelot – Thomsen Principle
Julius Thomsen
Marcellin Berthelot
(1826 – 1909)
(1827 – 1907)
All chemical changes are accompanied by the production of heat and that processes
which occur will be ones in which the most heat is produced.

2. Steam Engines
Rankine Cycle
Camshaft
Red = Hot Steam
Yellow = Exhaust

3. Gasoline (Four-Stroke) Engine
Otto Cycle
Nikolaus Otto

4. Engines and Refrigerators

5. Second Law (Kelvin Statement)
Lord Kelvin
(1824 – 1907)

6. Second Law (Clausius Statement)
Rudolf Clausius
(1822 – 1888)

7. Boltzmann’s Approach to Entropy

8. Molecules as Marbles Randomness is a powerful driving “force”!
1 Possible
144 Possible
4356 Possible
Randomness is a powerful driving “force”!

11. Entropy vs. Temperature
Copper Metal
Temperature [K]
Entropy [Joule/K mol]
273
31.0
295
32.9
298
33.2

12. Entropy and Phase Type Sodium (Na) Water Graphite 51.4 69.9 5.7 153.6
188.7
158.0
Solid
Liquid

13. Entropy and Atom Size Li Na K Rb Cs 152 186 227 248 265 29.1 51.4 64.7
69.5
85.2
Radius [pm]
Entropy [J/K mol] HF
HCl
HBr HI
173.7
186.8
198.6
206.3
Entropy [J/K mol]

14. Entropy and Molecular ComplexityNO
NO2
N2O4
211
246
304
Entropy [J/K mol]
CH4
C2H6
C3H8
C4H10
186
230
270
310
Entropy [J/K mol]

15. J. Willard Gibbs
(1839 – 1903)